separate xfer method.

Add missing .alloc_iob entries to several xfer_interface_operations
structures.

We didn't specify values for MaxRecvDataSegmentLength and
MaxBurstLength (to save space, since we were happy with the
RFC-defined default values of 8kB and 256kB respectively).  However,
the OpenSolaris target (incorrectly) assumes default values of zero
for these parameters.

The upshot was that the OpenSolaris target would get stuck in an
endless loop trying to send us the first 512-byte sector, zero bytes
at a time, and would eventually run out of memory and core-dump.

Fixed by explicitly specifying the default values for these two
parameters.

list.

Added FEATURE() macros to most relevant (non-driver) files.

and generate DHCP options to indicate features to DHCP server (and to
PXE NBPs).

really ugly hack at present, but that doesn't hugely matter since I'm
aiming to change the interface to iSCSI devices anyway within the next
week.

SCSI interface not yet implemented.

elsewhere as well.

will enable us to cascade async operations, which is necessary in order to
properly support DNS.  (For example, an HTTP request may have to redirect
to a new location and will have to perform a new DNS lookup, so we can't
just rely on doing the name lookup at the time of parsing the initial
URL).

Anything other than HTTP is probably broken right now; I'll fix the others
up asap.

may be called during the RX data processor, before the RX engine
transitions back to idle.  It doesn't really matter if the RX engine
isn't idle when iscsi_done() is called, because it will just pick up
where it left off on the next call.  (The same is not true for the TX
engine, so keep the TX engine assertion.)

reopen connection.  (The TCP API will soon change to render this step
unnecessary.)

TargetAddress from the login response, because we still need the old
address while we close the connection!

phase.  In iscsi_issue(), detect this state and immediately refuse the
operation.  This avoids trying multiple logins when scsi.c tries
several times to read the drive capacity.

reconnection mechanism.  This avoids the problems of trying to reuse
the TCP connection structure before the old connection has cleanly exited.

Added CHAP authentication

negotiation phases, to allow inclusion of CHAP authentication.

against NULL.

Start updating iscsi.c to use Nikhil's TCP API.

transition away from uIP.

Prepared ipv4.c for transition away from uIP.

orders of magnitude.

options even when we want to use the defaults.

the kernel), which encapsulates the information needed to refer to an
external buffer.  Under normal operation, this can just be a void *
equivalent, but under -DKEEP_IT_REAL it would be a segoff_t equivalent.

Use this concept to avoid the need for bounce buffers in int13.c,
which reduces memory usage and opens up the possibility of using
multi-sector reads.

Extend the block-device API and the SCSI block device implementation
to support multi-sector reads.

Update iscsi.c to use user buffers.

Move the obsolete portions of realmode.h to old_realmode.h.

MS-DOS now boots an order of magnitude faster over iSCSI (~10 seconds
from power-up to C:> prompt in bochs).

errors; still need to verify data integrity).

SCSI response PDUs are handled: status and sense data (if available) are
returned via the scsi_command structure.

Updated iSCSI session parameter usage.